Contents

Chapter Description

Designing a networking solution with the intent of bringing it to fruition through implementation is a business transaction. It is in your and the design process's best interest if that transaction is perceived by an SMB as valuable. This chapter will help you do just this.

From the Book

The past two decades saw the commoditization of computer networking in the
small-medium business (SMB) arena. In 1980, DEC, Intel, and Xerox (DIX)
published a document known as the "Ethernet specification," the
"Ethernet version 1," or the "Blue Book." In 1982, that
document was updated to Ethernet Version 2. Espec-2 remains a valid and relevant
standard even now, but it is much easier to set up a computer network today than
it was back then.

Think for a moment about the networking hardware used in the early 1980s: 10
Mbps shared media, network interface cards (NICs) with external transceivers,
vampire taps, thick coaxial cable, and repeaters to extend the network topology.
In terms of networking operating system (NOS) software, think of minicomputers
or mainframes; there were no viable network operating systems for PCs in 1982,
although fledgling efforts were under way to develop them.

Add to those mental pictures (if you can still imagine them) PC platforms
equipped with a whopping 640 KB or 1 MB RAM and CPU clock speeds of 4 MHz. You
are now on the cutting edge of networking and PC computing of the early 1980s!
And the aforementioned items were not available in office supply stores or
online. Why? For the simple reason that in 1982, even though the precursor of
the Internet (the ARPANET, developed by the Advanced Research Project Agency
[ARPA] in 1969) was in existence, today's web-oriented Internet, which,
using TCP/IP protocols, allows us to make online purchases with a click of a
mouse, was not. In addition, the high cost and limited availability of
networking and computing products in those days did not make them viable
candidates for the shelves of office supply stores.

Fast-forward more than a couple of decades to today. Networking products like
10/100/1000 Mbps NICs, hubs, routers, switches, relevant cabling, firewalls, and
plentiful high-performance PC hardware and software are commodity items. They
are available at many types of brick-and-mortar outlets, from electronics stores
to office supply stores to regular department stores. In addition, hundreds if
not thousands of other networking products from numerous vendors (both hardware
and software) are available at online stores and Internet auction sites. These
products range from basic equipment that is applicable for home networking to
complex multiservice devices and software applications that support the
operations of even the largest of enterprises. Given the fierce competition in
the networking field, many Internet sites specialize in providing price
comparisons to allow potential buyers (from home users to SMBs and large
enterprises alike) the option of purchasing a desired product at the lowest
possible price.

One thing is certain: Wide availability of networking products has made them
affordable (and indispensable, it is probably safe to say) to support the
endeavors of every business category, including all sizes of SMBs. Many of the
currently available networking products are also easy to use and to install,
especially when they are deployed individually or in smaller networks. The
network equipment vendors (including Cisco) are to be congratulated for making
networking hardware and software easier to use.

At the same time that ease and simplicity have been prevailing for home users
and small office/home office (SOHO) users, there has been a growing diversity
and an increase in sophistication and capabilities of the networking gear,
software, and business solutions meant for SMBs and large enterprises. Take IP
Telephony, for example. All of the IP Telephony solutions operate over a data
network (packet-switched) infrastructure and can nicely integrate with the
circuit-switched legacy installations. Consider that telephony has been evolving
for more than 100 years. Porting the existing telephony features, adding new
ones, and providing for integration of IP Telephony with the existing telephony
systems implies a degree of complexity and sophistication that is not exactly a
"plug-and-play" operation yet. Progress is continuous, though, and
even as this book is being written and released, Cisco and other IP Telephony
vendors are crossing the technical chasms. IP Telephony solutions are discussed
in more detail in Chapter 8, "IP Telephony Solutions."

When you combine the increasingly growing intelligence and capabilities of
the networking equipment with the diversity of the SMB landscape, as discussed
in the next section, it becomes advisable for anyone designing a network to
adhere to a principle that seems to have withstood the test of time: Effective
computer networks and networking solutions cannot be slapped together without
going through a design process. If you do not follow this principle, the
potential is too great for underutilizing the network capability and having an
SMB operate in a reactive mode with the limitations and quirks of the poorly
operating network driving business decisions rather than supporting them.
Computer networks and networking solutions need to be designed and implemented
to support the business and its mission instead of businesses barely making it
or going under because of their networks.

One Name, a Multitude of Shapes and Sizes

Trying to fully categorize and analyze the SMB market might best be left to
the market research firms, the Small Business Administration (SBA) in the United
States, or the equivalent government institutions in other countries. Suffice it
to say that it is hard to get out of bed in the morning and get through a day
without numerous encounters with SMBs. Even though some businesses you encounter
might seem to be large enterprises, from the perspective of designing a
networking solution, those enterprises are composed of smaller units that
effectively function as SMBs that are integrated with a high-capacity,
high-performance core network architecture that a single SMB might not require.
Effectively, on the edge of a network, even the largest of enterprises,
regardless of its sector, size, or shape, can be thought of as an SMB. And even
though networking solutions need to be tailored to support each SMB sector and
size category, a commonality of the networking infrastructure and solution
functions applies to the entire SMB landscape.

Business Sectors

SMB sectors span the alphabet, from automotive dealers through zipper repair
shops and zoos, including everything in between: education, travel, health
care, finance, legal, delivery, entertainment, food services, manufacturing,
transportation, and real estate, just to name a few. These businesses serve the
varied and ever-evolving needs of the societies that we live in, but at the same
time they share three common fundamentals: They all offer a product or a service
to a group of customers; they all have to remain competitive and fiscally
responsible if they expect to survive and to prosper in the marketplace; and,
generally, they all are working toward a certain goal. In for-profit
organizations, the objective is most often profitability; for nonprofits, the
goal is to offer a valuable service or a product that a society has deemed
worthy of not being subject to taxation.

All SMBs, regardless of the sector in which they operate, rely on utilities
that are now routinely taken for granted in a modern society: electricity,
telephone service, running water, or physical mobility through a
well-established transportation network. Computer networking has not been around
for as long as electric service, telephones, or divided highways, but from my
perspective, it is well on its way to becoming one of the common utilities.
Consider electricity. Numerous appliances performing a seemingly unimaginable
number of functions plug into standardized electric outlets to support the
complex requirements of our lifestyles. Consider a well-designed computer
network. Well, we are not quite there yet (being able to plug several
different devices into the network and having them work instantly), but progress
is heading in that direction.

A well-designed network should transparently support a wide range of business
applications to advance the varied missions of SMBs and other enterprises,
regardless of their size. Certain generic applicationssuch as payroll,
billing, accounts receivable, or electronic mailare common across all of
the business sectors, although their specific features vary as a function of the
size of the enterprise that they support. Other applications are unique to each
sector, including specialized banking software, inventory control for retail
outlets or wholesale distributors, automated production controls in
manufacturing facilities, or custom programs that access patient databases in
health care facilities. Often, the effective use of these unique applications
ultimately offers an SMB a competitive edge and supports the fundamental
business mission of delivering value to customers.

Consequently, when designing an SMB networking solutionsubject to the
design guidelines discussed in Chapter 1, "Effective Networking Solution
Design Process"it is important to keep in mind the ultimate
goal that the solution will support, regardless of the business sectors
that SMBs find themselves in. Supporting existing or future applications is,
needless to say, extremely critical. A security solution is necessary to protect
the effective functioning of the business applications and the attendant
information that they generate. But remember that although a security solution
might appear attractive in and of itself, to be effective and useful, it must
integrate well with the existing applications. If this sounds like an
implementation rather than a design issue, keep in mind that the line separating
the two is often thin. That is true especially in the minds of
stakeholders, who have a keen interest in the final outcome of a solution rather
than in maintaining a technical separation between the two stages (design and
implementation) relating to a solution's deployment.

When it comes to the design and implementation stages of a networking
solution project, careful management of stakeholder expectations is critical
when a proposed solution is a replacement for something already in
existence. Consider IP Telephony, for example. If you are considering a
brand-new telephony deployment, chances are that IP Telephony solution(s)
will win compared to their circuit-switching siblings because IP Telephony
solutions facilitate effective and inexpensive business communications.

However, because telephony has been around much longer than computer
networking, IP Telephony solutions will more than likely replace or
significantly upgrade the existing telephony infrastructure. The SMB might be
willing to live with the limitations of its existing installation if a
significant investment in it has already been made that would have to be
scrapped to proceed with the new solution. Thus, deploying a brand-new solution
is quite different from replacing an existing, functioning one. During the
design stage, the issue of implementation needs to be considered in much more
depth for significant upgrades or replacements than for a brand-new deployment.
This principle applies across all business sectors and sizes.

Business Sizes

From the point of view of designing a computer network or a networking
solution, the business size influences the quantity of equipment, the level of
its performance, the layout or network topology, and the interconnections
between the networking equipment. Business size should not necessarily affect
the type of functions that a network offers.

At a minimum, basic functions for the network in any size business should
include the following:

Internal and external connectivity for resource, file, and database
sharing

Support for common and specialized applications

Security

In environments with existing legacy networks, you always need to ensure
interconnection with legacy equipment and support for legacy applications. The
business size might well determine the following:

Whether the typical three layers (access, distribution, and core) are
going to remain distinct or be collapsed into one or two layers

Whether a single integrated appliance will be able to accommodate the
relevant business needs (LAN/WAN connectivity and security, for example) or
whether discrete devices optimized to perform routing, switching, or security
functions are required

Consider a small office with a dozen or so employees occupying a fraction of
a large office building. Then consider an enterprise with thousands of employees
occupying several office buildings. What is the difference between these two
environments from a network solution design point of view? Think about
modularity and scalability. In every product categorywhether it is
routers, switches, firewalls, or telephony solutionsCisco offers a
scalable spectrum of products to accommodate a spectrum of business sizes. At
the lower end of the spectrum, the approach might be to use fixed configuration
and/or integrated products. Refer to Chapter 5, "Cisco Security
Solutions," for a discussion of the spectrum of security products and
solutions.

As you progress through the SMB size scale, a modular design approach using
specialized blades that support routing, switching, security, or IP Telephony
from a single chassis becomes more preferable and cost effective. A larger SMB
size translates into higher capacity and higher port density on
fixed-configuration switches or on blades for modular switch units, routers that
switch more packets per second, or firewalls that support more simultaneous
connections. Modularizing the SMB or even a larger enterprise into distinct
units, applying appropriate product categories to those units, and integrating
those units via a logically hierarchical topology is a key concept in designing
scalable solutions for SMBs of varying sizes.

Business Missions

A business mission, often nicely framed and gracing the walls of the business
establishment, proclaims the reason that a particular business exists. It might
take a creative imagination to establish a connection between a business
mission and a router, a switch, or a firewall humming along on a rack in a
telecom closet, a data center, a dusty crawl space, or perhaps even under
someone's desk. However, if you choose to accept the premise that a
computer network is becoming as important as a common utility, those very
devicesif configured and operating properlyare as important to the
fulfillment of those flowery mission statements as employees being able to
transport themselves to their places of work, the business having reliable power
for all of the necessary office equipment (not just the networking gear), and
workers being able to communicate via a variety of telephony services.

You ought to be willing to establish a working relationship between a
business mission and the networking equipment or solutions. Take a moment to do
the following:

Clearly articulate how the existing network infrastructure and solutions
support or detract from the fulfillment of the mission.

Consider the impact on the business mission if the network or any
specific solutions suddenly disappeared and were not going to be available for
varying periods of time.

This exercise affords you and all of the stakeholders a bird's eye view
of how a new solution is likely to support the mission. And having that
bird's eye view provides a necessary refocus during the design stage, when
it is easy to lose sight of the ultimate purpose of the design because of the
extreme amount of technical detail that must be considered during the design
process.

The Pitfalls of the One-Size-Fits-All Approach

Up to this point, the commonality of different SMB types has been stressed in
the context of designing a computer network or a networking solution. But even
if a network is perceived as a common utility, it is quite obvious that to
function properly, the utility delivery systems need to have a proper
hierarchical structure to provide effective servicefor example, a city
water main and high-voltage transmission lines do not terminate at people's
homes or at small office buildings. In networking, the logical layers (access,
distribution, and core) as well as the level of equipment performance
approximate the hierarchies of the common utilities.

The one-size-fits-all approach might attempt to use similar equipment at all
network layers and not recognize the need for varying levels of performance of
the solutions discussed throughout this book. At one extreme, the pitfall of the
one-size-fits-all design approach is overdesign, making the SMB pay for a level
of performance or capacity that is much higher than it needs and that is out of
range for the business model. This strategy might be adopted so the SMB can use
the same equipment models throughout the enterprise. If the SMB makes a
conscious decision that the lower support costs resulting from that approach
offset the higher equipment costs, there is nothing wrong with this approach.
However, this consideration should appear in the design document.

The other extreme of the one-size-fits-all approach is not having sufficient
capacity or level of performance at the core or distribution layers. This
happens for exactly the same reason as overdesign: The SMB is trying to use the
same equipment models throughout the enterprise to save on support and/or
configuration costs. Thus, when considering the deployment of either an isolated
or an end-to-end networking solution, it is critical to distinguish between the
common functions of solutions that span the business sectors, sizes, and
missions and the elements of solutions that need to be customized, mostly in
terms of equipment models and levels of performance. Common solution functions
include the following:

The generic ability to move information between locations (routing and
switching)

Providing security in terms of confidentiality, information integrity, or
prevention of the denial of service

The ability to support and to integrate with applications

Within each of the preceding common functions, the solution differentiators
that must be observed across the spectrum of SMB types and sizes to avoid the
one-size-fits-all pitfalls are as follows:

The level of performance of routers and switches

The degree of security or the use of integrated versus single-purpose
security devices

The configuration customization that is required to support specific
applications